Spark-plug



J. J. LESTER, JR.

SPARK PLUG.

APPLICATION FILED Aue zo, 1920.

Patented Dec. 27, 1921.

@i o (I I To all whom it may concern:

naomee.

Be it known that I, JAMES JoHN LEs'rnR, Jr., a citizen of the United States, residing at Green Bay, in the county of Brown and State of Wisconsin, have invented certain new and useful Improvements in a Spark- Plug, of which the following is a specificae .and has for one of its objects to improve the construction and increase the efiiciency and utility of devices of this character.

Another object of the invention is to provide a device of this character having an.in-' creased firing facewhich may be increased and decreased in intensity by adjusting the electrode carrying rod. With these and other objects in view, the. invention consists in certain novel features 'of construction as hereinafter shown and described and then specifically pointed out in the claims, and in the drawings illustrative of the preferred embodiment of the invention. I

Figure 1 is a longitudinal sectional elevation of a spark plug constructed in accordance with the. invention,

Fig. 2 is a bottom plan view of the same,

Fig. 3 is a side elevation,

Fig. 4 is a detached perspective view of the rod carrying the improved form of electrode,

Fig. 5 is a detached perspective view of the improved form of the electrode carried by the bushing or body.

The improved deviceincludes a bushin or body represented as a whole at 10 and longitudinally bored and having an internally threaded socket 11 at one end larger than the bore whereby an annular shoulder 11 is formed therein, as shown.

Fitting within the body 10 is a relativelylong sleeve 12 of non-conductive material, such as porcelain, and held within the body by a clamp member or nut 13 threaded to engage the threaded socket.

Gaskets 14 and 15 of copper or the like are interposed between the sleeve 12 and the body 10 and between the sleeve 12 and the clamp member 13, as shown.

Extending through the sleeve 12 is a rod 16 having an intermediate stop collar 17 to limit the movement ofthe rod in one diwith to form a binder son of its relatively Specification of Letters Patent. Patented Dec, 27 1921, Application flled Augu st 20, 1920. Serial No. 404,876.

clamp nut 18 and washer 19, to limit the movement of the rod in the opposite direction. Another binder nut 20 engages the rod externally of the nut 18, coacts thereost, to secure and hold the conductor wire not shown).

At its lower end the rod 16 is formed with a lateral offset 21 semi-cylindrical in outline, or with a segmental face 22.

The face 22 is in the form of a semi-circle, as shown in Figs. 2 and 4, and the outer face curved longitudinally of the axis of the rod.

The offset forms an electrode and by realong curved face presents a correspondingly increased sparking surface. Another electrode is attached to the body 10 and includes a stem 23 diverging from the body and provided with a segmental extension 24, the latter curved to correspond to the curvature of the electrode 21 and with its inner concaved face. spaced uniformly therefrom and thus maintained equi-distant at all times-from the rod carried electrode, and the reversely longitudinally curved faces coact to diffuse the arc downwardly and in the direction of the fuel charge, thereby materially increasing the efliciency of the sparking action and likewise effectually preventing the. deposit of carbon thereon.

The arc..of the plug is thus materially extended without material increase in expense or'weight.-

The preferred embodiment of the invention is disclosed in the drawings and set forth in the specification. but it will be principle of the invention or sacrificing any of its advantages. What I claim is:

' 1. In a spark plug including a conductor rod having an electrode formed with a segmental face curved longitudinally of the axis of the rod, and a curved electrode spaced uniformly from the segmental electrode with its inner face curved reversely to the curvature of the longitudinally curved face of the segmental electrode, whereby the arc is diffused downwardly in the direction of the fuel charge.

2. In a spark plug, a supporting body, a sleeve of non-conductive material within said body, a rod extending through said sleeve, an electrode extending laterally from said rod and formed with a segmental face curved longitudinally of the axis of the rod, and a curved electrode spaced uniformly from the segmental electrode with its inner face curved reversely to the curvature of the emes longitudinally curved faces of the segmental electrode, whereby the arc is diffused downwardly in the direction of the fuel charge. 10

In testimony whereof, I affix my signature hereto.

JAMES JOHN LESTER, JR. 

